The rotor of a gas turbine has a rotor shaft and a plurality of blades mounted on the rotor shaft. Each of the blades has a blade body that extends in a radial direction of the rotor shaft, a platform that is formed at a radially inner side of the blade body and defines a part of a combustion gas flow channel through which a combustion gas flows, and a blade root that is formed at the radially inner side of the platform and is mounted on the rotor shaft.
Since the blades are exposed to a high-temperature combustion gas, for example, as described in Japanese Unexamined Patent Application, First Publication No. H11-247609 below, the blades are cooled by cooling air.
To be specific, the blade body, the platform, and the blade root are formed with a plurality of blade air passages which extend in the radial direction of the rotor shaft and connect the inside of the blade body and the inside of the platform and through which the cooling air flows. The plurality of blade air passages are arranged along a chord of the blade body. For convenience of the following description, an extending direction of the rotor shaft is defined as an axial direction, a radial direction of the rotor shaft is simply defined as a radial direction, and a circumferential direction of the rotor shaft is simply defined as a circumferential direction. Also, a side to which the combustion gas flows in the axial direction is defined as a downstream side, and the opposite side is defined as an upstream side. Further, a suction side of the blade body in the circumferential direction is defined as a circumferential suction side, and a pressure side of the blade body in this circumferential direction is defined as a circumferential pressure side.
The platform of an example of Japanese Unexamined Patent Application, First Publication No. H11-247609 is formed with a plurality of passages that extend from the plurality of blade air passages toward the circumferential pressure side and are arranged in the axial direction. All of the plurality of passages are open at an end face of the platform at the circumferential pressure side. Further, this platform is formed with a plurality of passages that extend from the plurality of blade air passages toward the circumferential suction side and are arranged in the axial direction. All of the plurality of passages are open at an end face of the platform at the circumferential suction side.
Also, the platform of another example of Japanese Unexamined Patent Application, First Publication No. H11-247609 is formed with a passage that extends from a first blade air passage at the most upstream side among the plurality of blade air passages toward the circumferential pressure side and then extends along the end face of the platform at the circumferential pressure side toward an axially downstream side. This passage is open at an end face of the platform at the axially downstream side. Further, this platform is formed with a passage that extend from the first blade air passage toward the circumferential suction side and then extends along the end face of the platform at the circumferential suction side toward the axially downstream side. This passage is open at the end face of the platform at the axially downstream side.